The good news about a lot of tropical destinations (depending on time of year, of course) is that there's usually a good breeze. An open hatch (esp fwd opening) in 15 knots of wind can create quite a gale below.. keeping things cool. Since you're also often at anchor this works well.

The opening ports on cabin sides do help, of course, but what sticks in my mind most about those is the chinese fire drill every night when a rain squall comes in to close them all, and then reopening when the rain passed. Many people add rainshields to these types of ports to help in that regard.

In lower breezes the various 'windscoop' devices also help to funnel breezes below for cooling.

Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)